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Please help! I've been stuck on these. Please show work. Thanks!!

 Feb 5, 2019
 #1
avatar+98153 
+1

20)     x - 2y  = 18   ⇒  x = 18 + 2y

Sub the into the second equation for x    and we have

 

-6(18 + 2y) - 4y = 4      simplify

 

-108 - 12y - 4y = 4      

 

-108 - 16y = 4            add 108 to both sides

 

-16y = 112            divide both sides by -16

 

y  =  -7 

 

And

 

x  =  18 + 2(-7)   =   18 - 14    =    4

 

 

cool cool cool

 Feb 5, 2019
 #2
avatar+98153 
+1

21) 

 

4x + 8y  = -16      (1)   

-8x + 10y = -20    divide through by 2  ⇒  -4x + 5y = -10     (2)

 

Add (1) and (2)    and we get that

 

13y = -26             divide both sides by 13

y = - 2

 

And using (2) to find x, we have

 

-4x + 5(-2) = -10

-4x  - 10 = - 10       add 10 to both sides

-4x = 0

x = 0

 

 

cool cool cool

 Feb 5, 2019
 #3
avatar
+1

Thank you so much for your help! I was so confused.

Guest Feb 5, 2019
 #4
avatar+98153 
0

OK....I  find the Sate of Confusion is one I occupy quite often...LOL!!!

 

 

cool cool cool

CPhill  Feb 5, 2019

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